Segregation of galactoside permease, a membrane marker during growth and cell division in Escherichia coli

Summary Incubation of Escherichia coli with chloramphenicol causes metabolic and biosynthetic disturbances, the best known of which is the synthesis of RNA and formation of incomplete ribosomes (chloramphenicol particles). As a result of the unbalanced biosynthesis the bacteria transferred in a growth medium exhibit a prolonged lag of recovery and also a lag before development of and lysis by phage 857 occurs. If lactose is the sole carbon source during incubation with chloramphenicol, the extent of these disturbaces is strongly dependent on the relative amount of -galactoside permease.This effect can serve to demonstrate heterogeneity of permease content in a population and permits to physically separate the fraction rich in permease.If bacteria fully induced for the lactose operon are grown without inducer, the permease is distributed among the progeny and unequal distribution will result in a heterogeneous population. It is shown, that using chloramphenicol treatment in the presence of lactose, followed by thermal induction of phage 857, bacteria previously deinduced during two doubling periods appear heterogeneous, about half the population being poor in permease.The significance of these results in terms of the pattern of growth of membrane is discussed.     

Amantadine-HCl (Symmetrel) in the Management of Parkinson's Disease: A Double-Blind Cross-Over Study

A double-blind cross-over study was carried out in 54 patients with Parkinson''s disease to evaluate the efficacy of amantadine hydrochloride as compared to a lactose placebo in the management of this illness. Amantadine proved to be a useful and safe addition to the armamentarium when given in daily doses of 200 mg. Forty-eight per cent of patients experienced moderate to good results while 31% showed no measurable improvement. The quality of the improvement was inferior to that obtained with levodopa, but the side effects were fewer. The study could not demonstrate a useful synergistic action between the two drugs, nor could the response to amantadine be used to predict that with levodopa. On the other hand, the addition of amantadine was useful in a few instances where optimal therapeutic doses of levodopa could not be given because of side effects. The mechanism of action of amantadine is still conjectural, but there is strong evidence to indicate some interaction with central dopamine metabolism.     

Drip Infusion Pyelography—Valuable Supplement to the Inconclusive Intravenous Pyelogram

By comparative studies of films, the superiority of infusion pyelography over conventional intravenous pyelography was confirmed.The technique is shown to be safe, even in the presence of uremia, diabetes, cardiovascular disease and advanced age.It is well suited for outpatient use, and should reduce the need for retrograde uretero-pyelography to supplement the diagnostically inconclusive intravenous pyelogram.     

GROWTH FACTOR INTERACTIONS IN THE TISSUE CULTURE OF TUMOROUS AND NONTUMOROUS NICOTIANA GLAUCA-LANGSDORFFII

Schaeffer , Gideon W., Harold H. Smith and Marion P. Perkus . (Brookhaven Natl. Lab., Upton, N. Y.) Growth factor interactions in the tissue culture of tumorous and nontumorous Nicotiana glauca-langsdorffii. Amer. Jour. Bot. 50(8): 766–771. Illus. 1963.—Tissues representing tumorous and nontumorous Nicotiana glauca-langsdorffii were cultured on high (5 ×) and low (1 ×) concentrations of a modified White's basal medium containing 2.9 × 10^–6m indoleacetic acid. The growth responses of tissues of both the tumorous and nontumorous genotypes to supplements of kinetin, glutamine, inositol and nucleic acid constituents added singly and in all combinations were noted on high-salt media. The nucleic acid components inhibited growth and were omitted from low-salt media. The best growth response was observed with glutamine and inositol for tissues from the tumorous hybrid and with glutamine, inositol and kinetin in the nontumorous type. Kinetin was a distinct and consistent requirement for rapid growth of nontumorous tissues, but no appreciable kinetin effect could be observed with tissues from the tumorous genotype.     

BIOTIC RELATIONSHIPS BETWEEN SOIL ALGAE AND OTHER MICROORGANISMS

Parker , Bruce C., and Harold C. Bold . (U. Texas, Austin.) Biotic relationships between soil algae and other microorganisms. Amer. Jour. Bot. 48(2): 185–197. Illus. 1961.—A study was conducted of biotic relationships between various algae and other microorganisms isolated from a sample of Texas soil. From 143 two-membered combinations of organisms tested in soil-water cultures, 3 were selected for detailed studies of the nature of the causal mechanisms of the associative effects. These were: (1) an association between a species of Bracteacoccus (Br. A-20) and a heterotrophic bacterium (B-6); (2) an association between a species of Chlamydomonas (Ch. 10) and a species of Streptomyces (Act-1); and (3) an association between a blue-green alga, Phormidium sp. (Ph. 14), and an as-yet-unidentified fungus (F-2). In the first association, the heterotrophic bacterium increased growth of Bracteacoccus up to 20 times in soil-water culture; the chief cause of stimulation was shown by a series of experiments to be the decomposition by the bacterium of complex nitrogenous substrates in the soil resulting in the release of simplified products which were available to the alga as a nitrogen source. In soil-water culture, Streptomyces (Act-1) enhanced the growth and motility of Chlamydomonas (Ch. 10) and induced akinetogenesis in the alga, while the actinomycete itself was stimulated in growth and production of conidia. The mutual stimulation was shown to be caused, in part, by carbon dioxide-oxygen interchange between the organisms. Motility of Ch. 10 was enhanced by a decrease in nitrogen as a result of the growth of Act-1 and by the ability of Act-1 to decompose and assimilate the extracellular polysaccharide of the alga. The assimilation of the extracellular polysaccharide by the actinomycete promoted its growth and conidia production. Initiation of akinetogenesis in Chlamydomonas occurred exclusively in close association with the filaments of Streptomyces in soil-water cultures, and only when the concentration of available nitrogen dropped below a critical level. The akinetogenic factor has not yielded to isolation and identification, but there is some suggestion that it may be an antibiotic substance. Phormidium (Ph. 14) was frequently antagonized and annihilated by fungus 2 in the soil-water medium. Attempts to extract growth inhibitors from filtrates of the fungal medium were unsuccessful. Indirect evidence suggested that perhaps the consumption of extracellular polysaccharide with concomitant release of organic acid by the fungus might be the factor inhibiting growth of Phormidium. Attempts to confirm experimentally the ecological significance for these biotic relationships are reported.     

THE NEWER PENICILLINS

The newer penicillins give high promise of overcoming some of the few disadvantages of penicillin-G.They fall into three groups: The alpha-phenoxy-penicillins; the penicillinase resistant penicillins; and the penicillins with enhanced activity against gram-negative bacteria.The newer alpha-phenoxy-penicillins offer little over alpha-phenoxy methyl penicillin (penicillin-V). As the length of the side chain is increased, absorption and attainable serum concentration is also increased, but these are questionable benefits and probably not significant for therapeusis.The penicillinase-resistant penicillins have once more brought almost all severe staphylococcal infections within therapeutic range. One of them, methicillin, must be administered parenterally. It is the agent of choice for the treatment of severe, penicillin-G resistant staphylococcal infections, and this is its only clinical indication. Another, oxacillin, which may be administered orally, is partially resistant to gastric acid degradation, but must be given on an empty stomach. It is most useful as prolonged therapy following methicillin, in the treatment of mixed hemolytic streptococcal-penicillin-G resistant staphylococcal infections, and as primary therapy for moderately severe penicillin-G resistant staphylococcal infections.The third group is still mostly in the experimental stage, but some strains of Proteus, E. coli, Salmonella and Shigella are highly vulnerable to their action.Toxic and allergic reactions to the newer penicillins, and crossed allergic reactions with penicillin-G, present unsolved problems.